Cardiac resynchronization therapy is achieved by positioning a lead in a traditional location in the right ventricle (RV), and by maneuvering a left ventricular (LV) pacing lead transvenously to a target wall in the left ventricle. Delivery of an LV lead to a desired location through the coronary sinus into the veins and their side branches surrounding the left ventricle is oftentimes a challenging procedure, requiring extensive fluoroscopic exposure for the patient and clinician. Venous anatomy is also highly variable, with some patients lacking suitable veins for permanent placement of a lead at a desired site, or requiring a lead to be maneuvered through sharp or even acute takeoff angles. Navigating a challenging anatomy may increase the possibility of complications such as coronary sinus or coronary vein dissection or perforation.
Fluoroscopic imaging during transvenous LV lead implantation may involve recording one or more two-dimensional (2D) cine loops depicting objects such as the lead within the heart during implantation and at the final position. Soft tissues tend to form outlines, rather than explicitly visible objects. Although the lead may be visible, it is implanted based on comparing real-time views of the lead as it is advanced into position with a pre-recorded venogram acquired with contrast agent to highlight the coronary sinus and its venous tributaries, or by using anatomical landmarks such as the spine. However, it may still not be possible to reach a certain branch with a lead due to small vein size, acute angulation, or tortuosity of the vein. It is oftentimes challenging to know a priori whether a particular lead would fit well within a particular branch and in which branch the lead would have a low chance of dislodgement. Furthermore, there are a variety of lead models with different lengths and diameters available, but the implanting physician may not be able to determine before the actual implant procedure whether a particular lead will fit in a particular branch. Thus, it would be desirous to be able to characterize the coronary venous vasculature prior to the implantation of a permanent lead.